1. The Field of the Invention
This invention relates to a novel poly(aminoamideureylene) resin, to a method for its synthesis, and to a novel use of the resin in the manufacture of paper and paperboard products. This invention also relates to improvements in the preparation of halohydrin-substituted polyamines. Lastly, this invention relates to an improved method for the preparation of hypohalous acid.
2. The State of the Art
Paper and paperboard products are generally manufactured by spraying a low solids slurry of pulp (called a "furnish") onto a moving porous conveyor. The water is removed to provide a wet sheet that is subsequently dried and further processed into a paper or paperboard product. Various compositions known as "sizes" are typically added to the furnish to improve the quality of the finished product. Other compositions are typically added to the furnish to facilitate processing; exemplary compositions include agents to facilitate drying of the paper and to increase the wet strength of the paper. These additives typically include polyamines or derivatives thereof which are treated to incorporate into the polymer quaternary ammonium groups and epoxide or halohydrin groups. Particular examples of resins are described by the following patents, the disclosures of which are all incorporated herein by reference.
As described by Keim, in U.S. Pat. No. 3,332,901, examples of such polymers are those having the formula --NH--(CH.sub.2).sub.n --NR--CO--(A).sub.m --CO--, in which R is alkyl or hydroxyalkyl, n is 2 or 3, m is zero or one, and A is an alkylene of one to six carbon atoms, --CH.sub.2 --NR--CH.sub.2 --, or --CH.sub.2 --CH.sub.2 --NR--CH.sub.2 --CH.sub.2 --, and aminopolyesters containing at least one tertiary amino nitrogen in the chain such as --(CH.sub.2).sub.n --NR--(CH.sub.2).sub.n --O--C(O)--(A).sub.m --C(O)O--, and polyaminopolyamides of the formula --NH--(C.sub.x H.sub.2x --NH).sub.y --CO--Z--CO--, in which x and y are each integers of two or more and Z is the divalent organic radical of a saturated aliphatic dicarboxylic acid containing at least four carbon atoms or an ester of a saturated aliphatic dicarboxylic acid containing at least two carbon atoms.
Maslanka, in U.S. Pat. No. 4,388,439, describes reacting the diester of oxalic acid with methylbisaminopropylamine (MBAPA) to produce a polyaminopolyamide which is subsequently reacted with epihalohydrin. The resin is stabilized with acids such as hydrochloric or hydrobromic.
Keim, in U.S. Pat. No. 4,501,862, describes a wet-strength resin derived from aminopolyamine-polyureylene, in which oxalic acid or its diester is reacted with urea and MBAPA to produce a resin that is subsequently reacted with epihalohydrin. The molar ratio of the oxalic acid to the urea ranges respectively from 0.1:1 to 10:1; and the molar ratio total of these components to the MBAPA ranges respectively from 0.9:1 to 1:2.
Maslanka, in U.S. Pat. No. 4,520,159, describes a process for producing polyaminopolyamides with halohydrin moieties by the reaction of a polyalkyleneamine having at least one secondary amine group with a dicarboxylic acid. The polyaminopolyamide is then reacted with allyl halide at a ratio of one to 11/2 mole per mole of secondary amine groups in the polymer to provide thereon a group convertible to a halohydrin moiety by the reaction of hypochlorous acid.
Bankert, in U.S. Pat. No. 4,419,500, describes the production of quaternized polyaminoureylenes having a halohydrin functionality by first reacting urea and a polyamine to produce a polyaminoureylene having at least one tertiary amine group, and then reacting the polymer with an allyl halide to provide a quaternized polymer having allyl-substituted quaternary nitrogens. The allyl substituents can be converted to halohydrin moieties by the reaction of hypohalous acid. Similar processes are described by Bankert in U.S. Pat. No. 4,354,006 and U.S. Pat. No. 4,419,498.
The use of epihalohydrins, and particularly epichlorohydrin, as the quaternizing agent for tertiary amine groups has become environmentally undesirable because of the toxicity of such compounds. Further, because substantially complete quaternization of the tertiary amine groups with the epihalohydrin in practice requires using an excess of the reagent, expensive recovery and purification techniques must be employed to produce a paper or paperboard product sufficiently free from epihalohydrin material. Accordingly, some of the aforecited patents describe reacting polyamines containing tertiary amines with an equimolar amount of an allyl halide compound to quaternize the tertiary amine groups, and then reacting the resulting product with hypohalous acid to convert the allyl moieties to the corresponding halohydrin moieties.